Metabolic and structural correlates of apathy induced by subthalamic stimulation

Objectives Apathy may be induced by subthalamic nucleus deep brain stimulation (STN-DBS) in Parkinson’s disease (PD). We therefore wished to test the existence of predisposing cerebral structural substrates and their functional correlates.

Methods Thirteen patients with PD who underwent preoperative three-dimensional MRI for cortical thickness analysis were assessed three months before (M-3) and three months after (M+3) STN-DBS with 18FDG-PET and the Apathy Evaluation Scale.

Results Decreased glucose metabolism induced by STN-DBS was correlated with increased apathy bilaterally in the frontotemporal opercular and orbitofrontal cortex. In most of these areas, negative correlations were observed between changes in apathy scores and cortical thickness.

Conclusions These preliminary results confirm that structural abnormalities correlate with postoperative increases in apathy and suggest that STN-DBS may induce functional impairment in these areas